Mysql 两种登入方式Socket TCP/IP

mysql的登陆方式有两种，分别是socket和tcp/ip方式登陆。

 

Socket（只能用于本地连接）

当server和client在同一台服务器上的时候，我们可以直接用mysql命令登陆。

[root@localhost ~]# /usr/local/mysql55/bin/mysql
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.5.60-log Source distribution

Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> status
--------------
/usr/local/mysql55/bin/mysql  Ver 14.14 Distrib 5.5.60, for Linux (x86_64) using readline 5.1

Connection id:		3
Current database:	
Current user:		root@localhost
SSL:			Not in use
Current pager:		stdout
Using outfile:		''
Using delimiter:	;
Server version:		5.5.60-log Source distribution
Protocol version:	10
Connection:		Localhost via UNIX socket
Server characterset:	utf8
Db     characterset:	utf8
Client characterset:	utf8
Conn.  characterset:	utf8
UNIX socket:		/tmp/mysql.sock
Uptime:			21 hours 40 min 17 sec

当什么参数都没有指定的时候，mysql默认使用socket方式登陆，如果/etc/my.cnf的[client]没有指定socket文件路径时，mysql默认会去寻找/tmp/mysql.sock，所以如果mysql服务启动的时候，生成的socket文件不是默认路径的话，登陆会报错（ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock'）。

[root@localhost ~]# cat /etc/my.cnf.bak

[mysqld]

datadir=/data/mysql

socket=/tmp/mysql.sock

mysql服务启动的时候，socket文件的生成目录可以在[mysqld]上指定，如果没有指定，默认是/tmp/mysql.sock。

 

 

TCP/IP（适合远程连接，本地也可以使用）

mysql登陆的时候，指定参数-h，会使用tcp/ip的方式连接，如果没有指定端口的话，默认是使用3306端口

[root@localhost ~]# /usr/local/mysql55/bin/mysql -h127.0.0.1   ----如果是两台服务器，在另外一台服务器需要连接该台服务器就要使用TCP/IP，socket就无法使用了
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.5.60-log Source distribution

Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> status
--------------
/usr/local/mysql55/bin/mysql  Ver 14.14 Distrib 5.5.60, for Linux (x86_64) using readline 5.1

Connection id:		4
Current database:	
Current user:		root@localhost
SSL:			Not in use
Current pager:		stdout
Using outfile:		''
Using delimiter:	;
Server version:		5.5.60-log Source distribution
Protocol version:	10
Connection:		127.0.0.1 via TCP/IP

 

 

Socket和Tcp/ip

当mysql登陆时，同时指定-h和-S，mysql会默认使用tcp/ip的方式连接。

[root@localhost ~]# /usr/local/mysql55/bin/mysql -h127.0.0.1 -S /tmp/mysql.sock
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 5
Server version: 5.5.60-log Source distribution

Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> status
--------------
/usr/local/mysql55/bin/mysql  Ver 14.14 Distrib 5.5.60, for Linux (x86_64) using readline 5.1

Connection id:		5
Current database:	
Current user:		root@localhost
SSL:			Not in use
Current pager:		stdout
Using outfile:		''
Using delimiter:	;
Server version:		5.5.60-log Source distribution
Protocol version:	10
Connection:		127.0.0.1 via TCP/IP